Calipers.



J. P. IRISH.

GALIPERS.

APPLICATION FILED MAR. 25, 1908.

921,407. Patented May 11, 1909.

JOHN F. IRISH, OF MILTON, MASSACHUSETTS.

1 CALIPERS.

Specification of Letters Patent.

Patented May 11, 1909.

Application filed March 25, 1908. Serial No. 423,224.

To all whom it may concern:

Be it known that 1, JOHN F. Inisn, of Hilton, in the county of Norfolkand State of Massachusetts, have invented certain new and usefulImprovements in Calipers, of which the following is a specification.

This irrxention relates to calipers and similar instruments particularlyof the type which comprises two legs pivotally connected at one end andhaving a spring tending normally to opening the measuring ends of thelegs.

The object of the invention is to provide a simple and reliablestructure of scale members carried by or connected with the adjustingmeans of the legs of the instrument whereby, when the legs are adjusted,the distance Or space between their free ends will be autonniticallyindicated by said scale members.

To these ends, my invention consists in the construction and combinationof parts sub stantially as hereinafter described and claimed.

Of the accompanying drawings in which similar reference charactersindicate the same or similar parts in all of the views,- Figure 1represents calipers, in elevation, illustrating a preferred embodimentof my invention. Fig. 2 represents a section on. line 92 of Fig. 1. Fig.3 represents a view from the right of Fig. 1, of the outer face of theadjusting nut and the end of the screw which passes through it.

The caliper legs a, which are shown as of a well known form, arepivotally connected at a and are normally pressed apart by a spring a".Mounted on the legs are the usual swiveled posts 7) 7) through which the1 screw 0 passes. The post 7) is not internally threaded, but the post 5is preferably internally threaded to fit the screw 0, and the jam-nut (Zis employed to secure or confine the screw 0 and prevent it from havingany longitudinal or rotative movement in the post Z). As stated,however, the screw passes freely through the other post Z). Fitted tothe screw 0 and so as to bear against one side of the post I), is anadjusting nut 6 having a peripheral portion 6' which may be milled. Thescrew 0 is flattened on one side and provided with a graduated scale f,the graduations of which cooperate with the face of the nut e in orderto indicate the distance between the ends of the caliper legs at anyadjustment. Preferably the face of the nut c is also formed with a scaleas indicated at g in Fig. 3, which scale will cooperate with one edge ofthe flattened periphery of the screw to indicate, by the rotation of thenut 19, fra j:tional measurements of less degree than what is provided.for by the scale 1. This practically constitutes a micrometer gage. Thecuts or the graduations of the scale or scales ar such, relatively tothe locations of the posts Z) 6 between the ends of the .rliper legs andthe pivotal point a, as to accurately indicate by means of such scale orscales the exact distance between the ends of the caliper legs at anyadjustment.

lVhile the invention is illustrated as applied to an instrmnenttechnically known as calipers, it is to be understood that I do notlimit myself thereto but may apply the same to similar instruments suchas dividers.

1. An instrument of the character described having its legs connected bya straight screw bearing a scale, means whereby said screw is pivotallyconnected to each leg. and an adjusting nut on said screw and having aportion cooperating with the scale to indicate the distance between theends of the caliper legs.

2. An instrument of the character described having its legs providedwith swiv eled posts, a screw fixedly mounted in one of said posts andpassing freely through the other post and having a scale, and anadjusting nut mounted on said screw and abutting against one side of thepost through which the screw passes freely, a portion of said nutcooperating with the scale on the screw, to indicate the spread of theends of said legs.

3. The combination with the legs of an instrument of the characterdescribed, of a screw fixedly mounted in one post and passing freelythrough the other, said screw having a scale the graduations of whichare arranged to indicate the distance between the ends of the caliperlegs at any adjust ment, and an adjusting nut n'iounted on said screwand having its face cooperating with the scale of the screw.

4. The combination with the legs of an instrument of the characterdescribed, of a screw fixedly mounted in one post and passing freelythrough the other, said screw having a scale the graduations of whichare In testimony whereof I, have aflixed my arranged to indicate thedistance between I signature, in presence of twowitnesses.

the ends of the calrper legs at any ad ust- JOHN R IRISIL ment, and anadprstmg nut mounted on sald screw and having its face cooperating withthe scale of the screw, the outer face of said nut having a circularlygraduated scale.

Witnesses A. V. Hnnmson', P. W. PEZZETTI.

